docs: def make_subdirs(self):
          """The purpose of this method is to, if necessary, create all of the
          subdirectories leading up to the file to the written."""
          # Pull off everything below the root.
          subpath = self.full_path[len(self.context.root):]
          log.debug("make_subdirs: subpath is %s", subpath)
          # Split on directory separators, but drop the last one, as it should
          # be the filename.
          dirs = subpath.split(os.sep)[:-1]
          log.debug("dirs is %s", dirs)
          current = self.context.root
          for dir in dirs:
              if dir:
                  current = os.path.join(current, dir)
                  if os.path.isdir(current):
                      log.debug("%s is already an existing directory", current)
                  else:
                      os.mkdir(current, 0o700)